Process of manufacturing varnish.



N0. 7||,596. Patented 001:. 2|, I902. A. L. TEDESCU.

PROCESS OF MANUFACTURING VABNISH.

(Application filed Feb. 27, 1902.)

(No Model.)

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HMUNNITED STATES PATENT ALOYS LOUIS TEDESOO, OF PARIS, FRANCE.

PROCESS OF MANUFACTURING VARNISH.

SPECIFICATION forming part of Letters Patent No. 711,596, dated October 21, 1902.

Application filed February 27. 1902. Serial No. 96,006. (No specimens.)

To all whom it may concern:

Be it known that I, ALOYS LOUIS Tnnnsoo,

1 a citizen of France, residing at 9 Rue Pigalle,

Paris, France, have invented an Improved Process for the Manufacture of Varnishes, of which the following is a Specification.

The manufacture of oil-varnishes containing gums (resins) comprises, in the first place,

pentine. In order to render them soluble,,the

gum-copal has to be heated to more or less high temperatures for a longer or shorter time, according to its nature, (soft copal, semihard, and hard.) The longer the copal issubjected to the action of heat the greater becomes its capacity for mixing with oils.

Hitherto copal has been generally heated in open apparatuses (matrass) or in ordinary still boilers, (the Violette process.) During this heating operation the volatile products (essential oils of copal) are continually given off, which constitutes a loss to the manufacturer varying from twenty-five per cent. to

forty per cent. and sometimes more of the Weight of the copal on starting the process.

The copals being always more or less mixed with foreign matter-such as leaves, fragments of wood, and the like, which the most careful sorting cannot entirely eliminate and the charring of which causes the production of particles of carbon, which brown or blacken the final prodnctthat is, the varnish. The

.processes which have been just mentioned,

therefore, place the manufacturer in the difficulty either of having to moderate the heating of the copals, and thus keep them below the temperature desirable for mixing with the oil, or else of havingto' augment or prolong the heating to avoid the first defect, and thereby infallibly obtain too dark a color.

The present invention relates to a new process for heating copal.

Thecopals,which are chemically-condensed terebenthenes, (according to Riban,) undergo under the action of heat a depolymerization or a deconcentration, which brings them back to the state of more simple terebenthenes, among which are easily found ordinary terebenthene and diterebenthene. We have astegral part of the constitution of the gum and the said terebenthenes falling back after condensation into the mass, the depolymerization takes place much more easily and, moreover, at a lower temperature, whence results much less colored products. The most simple process for attaining this result consists in heating the copal in a boiler surmounted by a top and by a reflux-condenser. stances as soon as the portion of copal most in contact with the source of heat begins to give off volatile terebenthenes these retained by the reflux-condenser fall back in a continuous stream on the substance not yet transformed, lnoistening it and by their presence and cooling action rapidly effecting the transformation of the rest of the copal in half the time. There is thus obtained a melted substance having the valuable property of mixing in any proportions with the raw, boiled,

or thickened oils which. are combined with In these circumbenthene and diterebenthenethe depoly- 'merization of the copal produced a certain quantity of acid liquids and some traces of alcohol, (principally methyllic.) Now it-is necessary to prevent these products falling on the untransformed copal, as they retard' and frequently entirely stop the depolymeriz ing action which the latter is undergoing.

The presence of these acid liquids is certainly the drawback which has caused the heating of copal in a Papins digester to be abandoned. In order to get rid of these liquids, I place in the condensing-cover substances capable of absorbing them-such as qu'icklime, chlorid of calcium, 850. Even more economical and practical would be to maintain at centigrade by means of a current of steam in a steam-jacket the temperature of the reflux-condenser, so that the terebenthenes (the ,most volatile of which boil at 156 centigrade to 160 centigrade) are retained in the retort, while the steam escapes. A second but descending condenser is placed after the reflux-condenser lower than the latprocess differ from those obtained inretorts org in the well-known distilling apparatuses, not only by their lighter color, but also by their special property (doubtless duetothe elimi nation of the acid liquid) of mixing with oils in any proportions. obtained are distinguished, moreover, by remarkable elasticity and gloss.

If by means of a pump or other suitable meansa more or lesscomplete vacuum be produced in the apparatus, the transformationof;

natural copal is mucheasier and takes place The oil-varnishes thus.

at a lower temperature, according to the degree of the vacuum. The p'roductsobtained are consequentlymuchmore discolored,.while. preserving their full power of absorbingoil.

It is necessary in making use of the vacuum to regulate the temperature of the refluxcondenser, according to the elastic forceof theaqueous vapor, to the pressure existing} in the apparatus, so as to eliminate the injurious liquid, while retaining almost the whole of the terebenthenes, which are volatile at a higher temperature.

By means of this process the loss is very inconsiderable, generally from five to six per cent. of the weight of copal treated. exceeds seven per cent. is only apparent, as will be proved.

The adoption of the second condenser allows It never; Moreover, this loss;

. maintained at 100 centigrade and forcing of collecting, mixed with water, all the terewater. This aqueous mixture is allowed to the total volu me, is removed.

.benthene which has been carried over by thei by means of one to two per cent. of quicklirne;

and can be used afterward.

It therefore follows that this process, while providing varnishes which are very much less colored, more resistant, and having remarkable properties of elasticity and gloss, never involves a loss of more than two and one-half per cent. to three;

per cent. of the copal treated.

As a rule the products obtained by this process are much more drying than the varnishes produced by heating in the open airor in the ordinary distilling apparatuses.

The accompanying drawing illustrates, by way of exam ple and diagrammatically, anapparatus suitable for the operation above described.

In this drawing, a indicates the boiler,

which is heated by a gas-jet b or any other convenient heating apparatus. A communication-pipe c connects to a vacuum-pump when such is made use of. A tube cl is provided for the removal of the volatile products. It is surrounded by a reflux-condenser e, which is filled with steam passing by the tube e and discharged by the tube 6 This steam at 100 centigradecondenses the terebenthenes, which fall into the boiler, and allows the acid-vapors to pass. The tube 01 is connected to a coil g, placed in a cooling vessel f with water circulating therein. The acid-vapors and the terebenthenes are condensed and collected in the receiver h.

What I claim is- 1. The process for the depolymerization of copals which consists in heating ,thecopals, in condensing the volatilized terebenthenes,

, and inreturningthesame to.the mass under treatment for the purposeof facilitating its depolymerization withoutaddit-ion ofiterebenthenes derived from other sources.

2. The processfor the depolymerization of copals which consists inheating the copals, in condensing the volatilized terebenthenes with separation and eliminatiomtherefrom of theacid aqueous liquid simultaneously volatilized and in returning the separatedpurified and condensed terebenthenes to the heated mass.

3. The process for the depolymerizationof copals which consistsin heating the copals (at the atmospheric pressure or in a more or less complete vacuum) undercondensingthe volatilized terebenthenes in a reflux -:condenser these condensed terebenthenes QtotalLback continuously in the smelting mass-and in si- ,multaneously separating the [condensed .tere- .benthenes fromthe acid liquidsia ndalcoholic vapors.

4:. In the process ,for.the-depolymerization of-copals, by the actof presence andfavorized by the cooling actionof condensedland purified terebenthenes derived from themass .by the aid of heat, collecting the acid andalcoholic liquids in a secondcondenser, allowing the mixed liquid to .stand until the .tereben- .thene carried over collectsatthe top, removing the terebenthene by decantation, deo dorizing it by meansof .one per cent. to two per cent. of quicklime in order to be utilized.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

PAUL FoURNoL, EDWARD P. MACLEAN. 

